"What then should we do?" was the question on the minds of John the Baptist's listeners we learn in this Sunday's gospel. It is also the question at the forefront of the debate over global warming. Political leaders and scientists gathered in Copenhagen this week for an international climate summit some dub the world's "last chance" to control warming.

At the same time the conference was getting underway the U.S. Environmental Protection Agency (EPA) announced Monday that greenhouse gases are endangering people's health and must be regulated. The move puts pressure on Congress to act on stalled climate legislation.

The ruling paves the way for regulation of carbon dioxide emissions from vehicles, power plants, factories, refineries, and other major sources. Industry groups quickly criticized the decision, saying that the regulation of carbon dioxide would be legally and technically complex and would impose huge costs across the economy.

EPA administrator Lisa Jackson said that the finding was driven by the weight of scientific evidence that the planet was warming and that human activity was largely responsible.

Jackson waded into the current dispute over leaked e-mail messages from a British climate research group that have stirred doubts among some people about the integrity of climate science. "We know that skeptics have and will continue to try to sow doubts about the science," she said. "It's no wonder that many people are confused. But raising doubts--even in the face of overwhelming evidence--is a tactic that has been used by defenders of the status quo for years."

Worldwide the vast majority of increased greenhouse-gas emissions is expected to come from developing countries such as China and India. But those countries have made it clear that their willingness to reduce growth in emissions will depend on what wealthier countries do first.

That puts a spotlight on the U.S. in Copenhagen, observers said, and the EPA announcement was timed to boost the Obama administration's case that the U.S. is indeed taking action to combat global warming even though Congress has yet to act.

In conjunction with the Copenhagen summit churches around the world this Sunday will ring their bells as part of what is being called "Hopenhagen," a call to action and prayer in response to climate change.

Source: Articles by John M. Broder for the New York Times, Dina Cappiello and H. Josef Herbert for the Associated Press, Jeffrey Ball and Charles Forelle for the Wall Street Journal, and Ecumenical News International